Many wing mounted, gas turbine/turbo fan jet engines are mounted on a pylon underneath the wing, such as that shown in FIG. 1. Because the engine is positioned for the optimum overall performance and operation of the aircraft and propulsion systems, the fan and primary nozzle exhausts of the engine are, very often, located under the wing. The pylon that supports the engine must be designed in order to minimize drag of the propulsion systems and the airplane. The pylon and sometimes wing, must be protected from the high heat generated by the primary nozzle exhaust with heat shields. Heat shields are positioned at the bottom of the aft portion of the pylon (aft pylon) and above the primary nozzle exhaust. Some heat shields are constructed of sheet metal, such as INCONEL.
When titanium became more available, titanium heat shields that were made using a titanium casting process replaced the sheet metal heat shields. FIG. 2 illustrates a cast metal heat shield assembly 10 that is mounted to the underside of an aft pylon assembly extending aft from approximately the exit of the primary nozzle of the turbo fan engine. The heat shield assembly 10 includes four components 12, 14, 16, and 18 that are all made of titanium and are produced by a titanium casting process. In the prior art example shown in FIG. 2, the component 12 is located closest to the primary nozzle exit and components 12, 14, and 16 are all designed with plume deflectors 20, 22, and 24. The plume deflectors 20, 22, and 24 are flanges located along the bottom corner edges of the components 12, 14, and 16. The components 12, 14, and 16 are designed in order to optimize aerodynamic performance with respect to the wing and airflow produced by the engine, i.e., the fan exhaust and the primary nozzle exhaust. The plume deflectors 20, 22, and 24 are designed (and shaped) to keep the primary nozzle exhaust and its high heat from reaching the portion of the aft pylon surface that is constructed of “low temperature resistant” material such as aluminum and/or composite. Because the prior art heat shield assembly 10 is made of titanium and formed by a titanium casting process, the cost of each heat shield assembly is very expensive due to the large number of complex steps required in the titanium casting process. The titanium is lighter in weight, strong, and very resistant to high heat. However, the cost of creating a cast titanium heat shield assembly is about two times more expensive than a comparable prior art sheet metal heat shield.
Therefore, to significantly reduce the recurring cost of the engine installation, there exists a need for heat shields having the lightweight and heat resistant qualities of a cast titanium heat shield at a production cost closer to that of a sheet metal heat shield.